George Zimmerman, who was not initially charged by police in the shooting death of unarmed teenager Trayvon Martin, was familiar with some of the officers in the Sanford, Fla., police department, having gone on several "ride alongs" with the cops, he told the city's mayor last year.

But Zimmerman, a criminal studies major, was harsh in his criticism of the cops he had met on the Sanford force calling their on-the-job conduct "disgusting."

Zimmerman, a member of the neighborhood watch, voiced his opinion at a January 2011 city commission hearing that included then mayor-elect Jeff Triplet.

One officer "showed me his favorite hiding spots for taking naps, explained to me that he doesn't carry a long gun in his vehicle because in his words anything that requires a long gun requires a lot of paperwork and you're going to find me as far away from it," Zimmerman said.

He added the officer "took two lunch breaks and attended a going away party for one of his officers."

These rides, along with new video showing Zimmerman roaming the police department unescorted just three days after the shooting, are reviving old questions of Zimmerman's relationship with the department that decided against charging him with a crime on the night of the shooting.

When ABC News asked the Sanford Police force in mid-March whether Zimmerman had any contact or relationship with the police force, the answer on more than one occasion was no.

"We do not have specific dates Mr. Zimmerman may have ridden or with whom he rode, if in fact he ever did ride with SPD," Capt. Robert O'Connor of the Sanford Police Department said in a statement today.

Zimmerman was later charged by a state prosecutor with second degree murder in Martin's death on Feb. 26.

These revelations come as a number of witnesses who claimed to have seen or heard parts of Zimmerman's fatal confrontation with Martin, apparently changed or expanded their testimony in the weeks after the shooting.

In a March 13 ABC News article on possible police missteps in the investigation, it was also noted that some of the witnesses felt that police had "corrected" their testimony.

Given that Zimmerman's trial may not take place for a year the memories of the dozen or so witnesses that dark rainy night -- memories possibly influenced evolving coverage of the case in the news -- would likely be hotly contested in court.

Among the witness versions that have changed are:

- Witness 5 told Sanford police investigator Chris Serino: "There was no fighting going on at the time the gun went off. We were both in the kitchen, the window was open. There was no fighting and the fight that happened." But in the 911 audio clearly includes what sounds like a struggle and a plea for help a split second before the gunshot is heard.

- Witness 6 is a man who lived near where the shooting took place and told Sanford police he saw a black man on top of a lighter-skinned man "just throwing down blows on the guy, MMA-style," and that the man getting beat up was the one calling for help.

But three weeks later when speaking with the Florida Department of Law Enforcement, he was no longer sure. "I truly can't tell who, after thinking about it, was yelling for help just because it was so dark out on that sidewalk," he said.

The man also said while he was positive that "the black guy was on top," he could no longer be sure Martin was throwing punches or simply trying to restrain Zimmerman.

- Witness 2, who is a young woman, initially spoke with Sanford police four days after the shooting. "I saw two guys running," she said. "Couldn't tell you who was in front, who was in behind." She said moments later she saw a fistfight: "Just fists. I don't know who was hitting who."

Nearly a month later when interviewed again, this time by the FDLE, her story had changed. She said she remembered catching only a glimpse of a single person running. "I couldn't tell you if it was a man, a woman, a kid, black, or white. I couldn't tell you because it was dark and because I didn't have my contacts on or glasses. … I just know I saw a person out there."

- Witness 13, who talked with Zimmerman in the moments after the shooting, didn't alter his account as much as he added to it. He initially told local police that Zimmerman told him that Martin "was beating up on me, so I had to shoot him," and that Zimmerman asked the man to call his wife and let him know what happened.

About a month later, the witness went into much great detail about Zimmerman's demeanor. Zimmerman's tone, according to the witness, was "not like 'I can't believe I just shot someone!'—it was more like, 'Just tell my wife I shot somebody …,' like it was nothing."

- A young mother identified as Witness 12 didn't give a recorded interview to Sanford police, but she did sit down with an FDLE agent more than three weeks after the shooting. She said she saw two people on the ground immediately after the shooting, but that she couldn't say whether it was Zimmerman or Trayvon on top. Six days later, however, she was sure it was Zimmerman.

"I know after seeing the TV of what's happening, comparing their sizes, I think Zimmerman was definitely on top because of his size," she said.